A tire having a tread provided with a running surface comprising a conventional rubber is known from the prior art. This running surface is intended to come into contact with the ground when the tire rolls on the ground.
More specifically, the running surface comprises various plies of rubber adapted to the rolling of the tire on the ground. These plies have high wear resistance properties.
In some cases, in order to limit the rolling noise of the tire on the ground, the tread is also provided with a layer comprising a cellular material. The cellular material comprises, for example, a foam, in other words a material in which cells are formed by gas bubbles.
Because cellular material wears away more quickly than conventional rubber, it has been proposed that the layer comprising the cellular material be positioned radially inwards from the running surface, the cellular material thus forming a sublayer of the tread.
The sublayer is therefore generally interposed radially between the running surface and a reinforcement having metal or textile reinforcers embedded in bodies of rubber.
When the tire is cured, a chemical reaction generates gas bubbles which form the cells of the cellular material. However, the gas which is formed may tend to accumulate in regions forming relatively large accumulation cells. If these accumulation cells are too large, or if they are located at the interface between the running surface and the sublayer, their pressure causes the running surface to be detached from the sublayer. In this case, the tire cannot be sold, because its reliability is not satisfactory.